Selective switching apparatus.



- A. RBIXON.

SELECTIVE SWITCHING APPARATUS.

APPLICATION FILED AUG. 10, 191?.

Patented May 19, l l.

7 SHEETs-SEEET l Q H 1| mam Nam fim mm mm Gm \k hum/770w Amos ff0/)(0/7. y/M W A7734 W/lnesses:

7 SHEETS-SHEET 2.

//7 van/0r Amos F Dixon W A ff A. P. DIXON.

SELECTIVE SWITCHING APPARATUS.

APPLIOATION TILED AUG.10, 1912.

Patented May 19, 1914.

A. I. DIXON.

, SELECTIVE SWITCHING APPARATUS.

APPLICATION IILIID AUG.10,1912.

Patented May 19, 1914.

7 SHEETS-SHEET 3.

Mvenfor. Amos 1. D/xon.

fly I M W Affy.

am mww 5 l p WW M A. P. DIXON.

SELECTIVE swmonme APPARATUS.

APPLICATION FILED A\UG.1U,1912,

n 3 1 Q97 54 Aatented May 19,1914

TS-SHEET Wfinwses: 1 m l/l? for: M A mos F Dixon.

LBIXON. SELBQIWB SWITOHING APPARATUS.

1131110111011 FILED AUG. 10, 1912.

Eatented My19,1914.

'7 SHEETS-SHEET 5.

Mme/war: Amos F D/xon. W

W/fnesses:

A. F. DIXON.

SELECTIVE SWITOEING APPARATUS.

- APPLICATION FILED AUG.10, 1912.

Patented May 19,1914.

7 SHEETSSHEET 6.

//7 van/0r: 14/7705 07x00.

W/Mesaes laz Affy- A. F. DIXON.

SELECTIVE SWITCHING APPARATUS.

APPLICATION FILED AUG.10, 1912.

1 097 540 Patented May 19, 1914 i 7 SHEETS-SHEET 7 l/V/fnessesx Q 92mmemorx W Amos fTD/xon.

ED 'sTATEs m hate AMOS F. DIXON, 0F NEWARK, NEW JERSEY, ASSIGNOR '10WESTERN ELECTRIC COMPANY, OF NEW YORK, N. Y., A CORPORATION 01*ILLINOIS.

SELECTIVE SWITCHING APPARATUS.

Application filed August 10, 1912. 7 Serial No. 714,386.

To all whom it may concern:

Be it known that I, Amos F. DIXON, citizen of the United States,residing at Newark, in the county of Essex and State of New Jersey, haveinvented a certain new and useful Improvement in Selective swltchmgApparatus, of which the following is a full, clear. concise, and exactdescription.

This invention relates to telephone enchange systems of the automatic orsem1 automatic type in which the selection of lines or trunks for theextension of telephone transmission circuits is accomplished bymechanical selector swltches, the ob cct being to provide an improvedarrangement of circuits, and apparatus whereby the selective operationsmay be accurately and speedily accomplished.

One feature of the invention involves controlling apparatus and aswitclnng mechanism capable of selecting a main group or bank ofterminals, a subordinate group of terminals in such main group, and orselecting an individual line in such subordinate group. v

Another feature of this invention involves means whereby a selectormechanism havingbeen so operated as to select a group in which thedesired line is located under the control of positively operated drivingmeans will be released from such means, and will thereafter select aparticular line with which connection is desired by intermittent releaseunder the influence of gravity.

In the drawings: Figures 1 and 2 illustrate the invention in connectionwith a single selector and a sender, the selector being one by which itis desired to select an idle trunk line to a further selector. F-ig. 3is a perspective view of the selector including the master drivingmechanism with the speed changing clutch and gearing which is common toa plurality of selectors. There is also shown in this figure one of theindividual mechanisms of this group of the selectors. All of thisapparatus is shown diagrammatically in 2. Fig. 4 is a longitudinalvertical.section, ofso much of the driving mechanism as is common to a'plurality of'selectors belonging to a particular group. Fig. 5 isatransverse vertical section of the commonl driving mechanism taken onthe line 5-5 of Fig. 4. Fig. 6 is a side View ofathe driving, holdingand release mechanism individual to each individ- Specification ofLetters Patent.

Patented New 129,

ual selector. Fig. 7 is a horizontal section of the individual drivingand release resellanism taken on the line 77 of Fig. 6. Fig. 8 is a planview of a sequence switch as used in connection with the sender anddriving mechanisms shown in Figs. 1 and 2. 9, 10, 11 and 12 are detailviews of the brush carrier used in the selector shown in Fig.2.

The scZect07.-The selecting mechanism in connection with which thisinvention is illustrated is shown partly diagrammatically and partly inperspective in Fig. 2. It is of the master and individual type ofmechanism, arranged to be operated on what is known as the panel form ofselector multiple. This multiple consists preferably of strips of metalhaving contact points spaced at regular intervals along their entirelength. These strips are placed one upon another with strips ofinsulating material between, in such manner as to form vertical banks ofcontacts over which the selector contact brushes can be moved/in avertical direction. The selector may comprise any desired number of setsof contacts and these contacts may be divided and subdivided into groupsas preferred. As herein described, however, the selector is consideredas accommodating contacts forming the terminals of five hundred trunklines, these five hundred trunk lines being divided into tive maingroups or banks of ;one hundred lines and each of these main grbups orbanks subdivided into ten subordinate groups of ten lines each. The tentrunk lines, the terminals of which form a subordinate group, are hereinconsidered as leading to apparatus having similar functions so that eachof the lines of a subordinate group will equally well serve vfor theconnection desired, but it should. be understood that this invention asherein involved is not limited to such con- Iii Fig. 2 apart of a bankof contacts as referred to above is indicated generally at 84. The setof contacts St and 87 form respectively the transmission and testterminals of the trunk line 303, 30% to a further selector. The brushcarrier 88 carries the brushes 89 and 90 arranged to contact,

respectively, with the ternjiinais 85 and, 86,

and the brushes 91 arranged to contactgwith the test-'tcrminil 8?. Thisbrush carrier, whichfis shown in detaii'fin' Figs. 9 10 v v id-T and i2and will he hereinafter moreisnecifially described, is carried by ametallic tape I hissing around .the sheave 7 6 of the d lug mechanismindividual to the selector and also over the pulley 93. This tape whenmoved by the rotation. of the sheave 76 carthe brushes into position tomake cont with the terminals 85, 86 and 87 of the sod trunk line, theselection being demined by the extent of the movement oi. zape, thecontrol of which will be here i after fully set forth. Brieflyconsidered, :a notion is accomplished by moving the brimh carrier, whichnormally stands at thos hottom oil'- the first main group of contactmain group, in which the vterminals of the.

edline are, located. The main and sub y group havingwhus been selectedthe. cular. set of termiiials in such subsidiary cup is selected by adownward step by movement of the brush carrier, whicl do onwardmovementmay be under the control of a sender or may be an automatic search foran idle line as is herein illustrated. i

shown in. Figs. 9 to 12 the brushes 89, and 911 are supported on acarriage 8S ably mounted upon a rod 941 which one ds the entire heightof the selector. This niage 88 is securely attached to the 1netallictape )9 by the screws 95, but is insulated therefrom by the insulatingbushings 96. The carriage itself is com osed of two body portions 9'?and 98 in orc er to render possible the accurate adjustment oi thebrushes with relation to the terminals and to the tape 92. Thisconstruction is shown. clearly in Fig 12, wherein the tape 92 is shownat tached to the part 98 and the brushes are carried'by the part 97, thetwo parts being securely fastened. together by means of the bolt 99while the-cooperating serrations 100 upon the parts 97 and 98 serve toprevent their disadjustment after they havebeen once secured, Thebrushes 89, 90 and 91 are so arranged, as will appear from. Fig. 12,that they make mechanical contact with one ton Ininal before leaving thepreceding one, but owing to the inserts of insulation. 101 upon theircontact faces, do not make-electrical contact with more than oneterminal at a time These brushes moreover are arranged.

out cl alinen'ient with each other in order to in them into properrelation with the irniinals 86, 87 which are an wf ll he seen from Figs.9, 10 and lation, the lcwermrost t e upperanost he.

lll. i iinal urinals, first by long steps and at a rela- 'jfurnishcspowerto the various apparatus cl noenani is necessary owing to theconstruction inclicated in Fig, 9, where it may be seen. that suchterminals are formed by projections upon the conducting pieces 102 laidbetween sheets of insulation 108 as is usual in the construction ofselectors of what is known as the panel type. The brushes 89, 90 and 91pivotally mounted upon the carriage 88 as will be readily seen and arepressed. into contact with the terminals 85, S6 and '87 by the springs109. The brushes 91 are in electrical connection through theirmountingwith the contact spring 104, which spring makes contact at all tuneswith the rod upon which the carriage moves, and thereby places thebrushes 91 in constant electrical contact with the rod 9 1 with whichthe selector test lead is electrically connected. The brushes 89 and 90are each mount-- ed upon a portion of the carriage insulated from eachother and from the )ortion on which the brushes 91 are mounts and eachin turn is electrically connected by means of the contact springs 105and 106 with the auxiliary rods 10? and 108 which also ex tend the fullheight of the-selector and serve to connect the transmission circuit tothe brushes 89' and 90.

Thedriving mechanism bywhich power is supplied for moving the brushcarrier 88 into cdntactual relation with the ten ininals 85, 86 and 87is shown in Fig. 2 by the master clutch. mechanism 1.3, common toplurality of selectors; the individual clutch .mechanism 14 and the seed changing mechanism 31 which is a. so common to a plurality ofselectors as indicated on Fig. The master clutch 13 comprises a shaft 15mounted. upon the uprights 1.6 extending from the base 17 and. has inturn rotatably mounted thereon a sleeve 18, at

one end of which is the disk 19 and. to the other end of which isattached the gearwheel 20. This gearwheel 20 is in permanent mesh withanother gearwhecl (not shown) upon a constantly rotating shaft, whichmay be, and is preferably, that which.

the exchange. Upon the shaft 15 is also mounted the sleeve 21 to oneend. of which is attached the gearwheel and to the other end of which isattached the disk :23. The disk 23, of soft iron or other magneticmaterial, forms the armature of the electrm magnet mounted. uponv thebase 17 and surrounding the shaft 15 and the sleeve 18. The d. k 19,which is'i'orrncd of brass or other nonmagnetic material, is providedwith a friction surface 26 arranged. to oppose and coiiperatc with thefriction surface 24 upon the central portion-of the dish or armature 23.a The circularpole-piece :27 surrounds the disl: 19 and when the i isenergi it att and brings the disks 19 and 23 into intimate frictionalcontact, causing the rotation of the disk 23. The arrangement of thedisks l9 and 23 with respect to the pole-piece 27 is such that when thedisk 28 is attracted, its-periphery will be closely adjacent to thepole-piece 27, in order that it may be firmly held in contact with thedisk 19, but will not be in actual contactwith the pole-piece Thegearwheel 22 meshes with the gearwheel 28 fixed upon the shaft 29, alsomounted upon the uprights 16, This shaft 29 has attached to one endclutch member 30 arranged to cot perate with a second clutch member 32of the speed reducing mechanism 31. Upon the shaft 29 are also mountedthe commutators and 3-1. The commutator 83 cooperates with the contacts35, 36 and serves to make and break the circuit between these contactsonce for every revolution of the shaft 29. The commutator 34: similarlycodperates with contacts 37 and 88 to make and also break the circuitbetweenthese contacts at each revolution of the shaft. The relation oftie make and break of the circuits between contacts and 36, 87 and 38,respectively, will be hereinafter referred to and set forth in thedescription of the operation of the system.-

lhe disk 39, which is also mounted on the shaft 29, has eotiperatingtherewith the ar 40 mounted upon the shaft 29 and held in particularrelation to the disk 39 by the springs 41, which are fastened at theirrespective ends to the disk and the arm. This arm e0 cooperates with thearmature 42 of the stop magnet l3 to stop the rotation of the disk 39when the magnet 43 has been deenergised, but to permit a slight oven runby the disk 39 due to the extension of the springs d1, which over-runwill, however, be corrected and the disk 39 brought back into properposition by the contraction of the springs ell. Cooperating with a notch4% upon the disk 39 is a pawl d5 mounted upon'the base 17 and soarranged that upon the reserve movement of the disk 39, due to thecontraction of the springs ll, the disk 39 may not by any mischance movetoo far in the reverse direction. By means the arm 10 and the pawl thedisk 39 when stopped by the armature 413 will always come to rest inprecisely the same position. The armature 42, which is normally in aretracted position, due to the tension of the retracting spring 46,operates when attracted for purposes hereinafter set forth to close thecontacts all and 48, which are mounted. upon an extension 4L9 from'thbase 17 insulated from each other and from the extension 49,

The speed changing niicchauism 31 comprises the gearwheel 51 affixed tothe shaft- 52, mounted upon the uprights 16, which gearwheel 51znesheswith the gearwheel upon the shaft 29. Also afiixed to the shaft 52 is agearwheel 54: which meshes with the gear-wheel 55 aiiixed to a sleeve 56mounted, but freely rotatable, upon the shaft 5t. This gearwheel 55carries a pawl '58 cooperating with the ratchet wheel 59 affixed to .theshaft- 57. Upon the end of the shaft 57 is mounted the sleeve 60longitudinally movable upon said shaft 57. To one end of the sleeve 60is attached the clutch member 32 cooperating with the clutch member 30upon the shaft 29, and u Jon the other end is adjustably mounted t edisk 81 forming the armature of the electromagnet 62 which surrounds theshaft 57 and the sleeve 60. The adjustable mounting of the disk 61comprises the threaded portion of the sleeve 60, the set screw 63 andthe adjusting ring 64. By this means the disk 61 may be so positionedthat upon the energization of the electromaguet 62 it will be broughtclosely adjacent to the circular pole-piece 65 of the electromagnet,thereby forcing the clutch member 32 into cooperative relation with theclutch member 30, but willnot actually come in contact with thepole-piece 65. Upon the deenergizatiou of the magnet 62 the disk 61 willbe moved, away from the pole-piece 65 and the clutch member 32 out ofcooperative relation "ith the clutch member 30 by the action of thespring 66. This spring 6 has one end abutting against a portion of theelcetromagnet 62, and the other end against the adjusting ring 65 insuch a manner as to move the sleeve (30 longitudinally upon the shaftwhen the electromuguet (i2 is deen- GI'QlZQLl, A portion of the sleeve60 extends longitudinally of the shaft 57 and is keyed into a recessedportion of the collar 67 fastened to the shaft 57. By this means thesleeve (50, although longitudinally movable upon the shaft 57, is notable to rotate without rotating the shaft 57 corres 'iondlngly. It will,therefore, be seen that the cpcration. of the clutch 13 by theenergizution of the elcctromagnct 25 will cause the shaft 57 to revolveas the shaft 29 revolves, either through the reducing gearing 53, 51. Sl, 55 and the pawl and ratchet 58, 55), or directly through the clutchmembers 30. 32 depending; upon the operative condition of the speelrhauuing clutch 68. The earing referred to, and which will be calledthe speed reducing gearing, is so constructed that when the speedchanging clutch 68 is at operatedthe shaft- 57 will revolve butone-tenth as fast as the shaft 29. The shaft 57 will, however, revolveat the same speed as the shaft 29 whenthe speed changing clutch SS isoperated, Upon the shaft 57 are fixed at proper intervals, as shown onFig. 3, the gearwheels 69 which transmitpower to the individual clutchmechanisms 14, but one of which is shown, however, in this figure.

(ill

[individual driving mcchoniem-The individual driving mechanism comprisesthe shaft to one end of which is atliXed the gearwheel 71 which mesheswith the gearwheel 69, above referred to, upon the main driving shaft57. Adjacent to the gearwhcel 71, and also affixed to the shaft 7 0 isthe disk 72 of soft iron, or other magnetic material, which forms thearmature of the electromagnet 73, which when energized attracts the disk72 to move the shaft 70 so that the clutch member 74.- lixed on theother end of the shaft is moved into cooperative. relation with theclutch member 75, fastened to the sheave 76 around which the metallictape 92 is adapted to pass. This sheave 76 has set in the peripherythereof projecting pins 77 which cooperate with the holes in themetallic tape to prevent the tape slipping upon the sheave. The shaft 70is normaliy held. in a position in which the clutch member 74: is out ofcooperative relation with the clutch member Toby means of the spring 78,as is plainly'shown on F i 7. The inner rim of the sheave 76 is ma e toform a ratchet by having cut therein the teeth 79. Cooperating withthese teeth? 9 is the armature S0. of the electromagnet 81 by adapted tobe attracted to remove the projecting piece 82 upon the armature out oilcooperative relation with the teeth 79. The armature 80 is normally heldretracted and. the projecting piece held in engagement with. the teeth79 by the spring 83. The movement of the sheave 76, therefore, de' pendsupon the cnergization of the clutch magnet 18 and the rotation oftheshaft 57. The shaft 57, however, having moved the sheave and tapeinto anygiven position they may be prevented from returning by theprojection -82 upon the armature 80 underthe control of the releasemagnet 81:.

Scouence StU't Z OJI/r- IO control the local circuits at the variousparts of the system, which lo al circuits must be established indefinite order at successive stages of the op eration, to bring intoservice dillerent de vices or parts as desired, there are usedantou'iatio switching; appliances which. are termed sequence switches.There is, for example, a sequence switch associated with the sendermechanism, a sequence switch associated with the master drivingmechanism and. a sequence-switch associated with each individual drivingmechanism as is indi cated upon Figs. 1 and 2 of the drawings. Thesesequence switches each consist of a movable switch operating member, anumber of circuit-changes being made in sequence as. saic member ismoved from one position to author; an electromagnet and a constantlysource of power, the connection of,

1b. H L movable" member: is con for advancing said to by on the facethereof adjacent to the di h? Ia friction surface of suitable materi theenergization' of which the armature is,

the sequence switch may be actuated, so that the sequence switch will.then be tlll lt lll'tl'l" cally advanced to the next position in. w anew set of circuits is established in orl to bringabout a new operationor elcctrn: condition of the device or device trol and so on. In the f:switch mechanism shown in Fir agrammatically shown on lligs. 1 and is ageaxwvheel driven by a constant? ing shaft, not shown. This ge isfixed'upon a shaft 171 mounted 1 base 172 and having at the end opp! Igearwheel 173, a disk 17% of brass or oil. non-magnetic material.Adjacent to U disk 174 is a dislt 176 fixed on the slip and forming thearmature of the clutch magnet 178.' This dish 176 is forin'nl or softiron or other magnetic material and l:

al 171 cooperating with a similar friction sur nim upon the disk 17 4.Upon the cum Jo tion of the electromagnet 178 the dis J76 will bedrawnadjacent to the circular polcpiece 180 of the electroniagnct, and willbe brought into intimate frictional contact with the disk 174 which isconstantly ro- MW tating' and the two disks will, therefore, rotatetogether. Upon the shaft 1'77 is also fixed a gearwhcel 18.1 whichmeshes with the gear-wheel 18?. fixed on a shaft 184; which is mountedon a base 183. On this shaft 18 i are fixed the cam wheels 185 made ofinsulation, upon the outer rim of which. are formed the cam surfaces 186which. coopcn ate with the contact springs 188 to force such springsinto and out of contactual relation with the various contact springs 18?and 189 as the cam wheels 185 revolve, the movement of the springs 188depending upon the formation and posit-ion. of the cam surfaces 186 uponthe cam wheels. Fae tened upon one end of the shaft 184- is a stop-wheel190 formed with notcbc ipon its periphery in which the projection 191.upon the armature 192- of the electromagn'et 193 is adapted. to restwhen said armature 1 is retracted to stop the rotation of the shaftpromptly and accurately when the position. desired has been reached andti elc magnet 193 has been. deenergized. spring 19% serves to retractthe armature 192 upon the deenergization of the electromagnet 193.

In Figs. 1 and 2 which. diagrammatic showing; of the i; switch springsof the sequence nooneeo not shown in their actual arrangement, but

are so located as to give a clear arrangement of the circuits, theoperatingcam wheels not btllQyElllOV/H. The positions of the rotaryelein' t of each sequence switch in which any t" its contacts, exceptthe respective special contacts 291, 391 and 191 are closed,

ind cated by the numbers placed adjacent to. such contacts; each contactbeing g {open in all positions except those indicated by such numbers.For example, the contact .13 in Fig. 2 is closed in the 2nd and 1thpositions of the master sequence switch as indicated by the numbers 2and 4: placed adjacent theretomnd is open in all other'pir In the caseof the special contacts 1. eterrcd to the numbers are placed ontheiaapcsite 51 do oi the switch lever from i:

contact anvil and indicate the positions it w ich the contactis open,this contact being closed continuously while the rotary element of thesequence switch is in transit and between. the positions indicated. Inall p; ltlOIlS the numbers of which appear adjacent to the specialcontacts these contacts are open to permit the respective sequenceswitch to come to restin the positions so indica l. I

5cm mg mecizau-ism-r-The selector shown may be controlled by sendingapparatus such, for example, that diagrammatically illustrated inFig. 1. As shown, this apparatus comprises a plurality of controllers221, 231; a sequence switch 251; a stepping relay 286; a cuboid" relay282 and a starting key 271. The controllers 221, 231, which may be ofany preferred construction and operated by any suitable means, are forsimplicity shown as comprising manually-set segments 222,

mounted at controlling contacts 220, 230, respectively. These segmentsare governed in their return to normal position, under the influence ofsprings 226, by the escapement pawls 227 which coiiperate with the teethupon the segn'icnts These pawls 227 are moved in one direction by theelectromagnets 22S and 238 and in the other direction by the retractingsprings 229, and are so a ugged that for each oscillation of the pawlsthe segments 222 will be allowed to return the distance of one tooth.The controllers 221, 231 in the construction shown are by means of thehandles 225, until the poi ter upon the handle is adjacentto the run erof the group in which it is desired that an dle line he found, to extendthe transml, "I the present showing the controller 221 serves toindicate and control the s l c' of the main group of lines in which edesired line is to be found and the controller to .rdicate the secondarygroup in such main group in which such line is to be found.

f'HMTnJLZW/L-Figs 1 and 2 show diagrammatically an embodiment of theinvention including a sender apparatus and a trunk selector. In thesefigures thc telephone transmission circuit 201, 202 is shown connectedby some selecting means, of common or well known design, to the trunkconductors 301, 302 at the contacts 305, 306. These trunk conductors301, 302 lead to a selecting mechanism by which such telephonetransmission circuit may be extended to the conductors 303, 30s or othersimilar conductors. The selector associated with the conductors 301, 302shown in Fig. 2 is one in which it is desired to select an idle trunk ofa certain group of trunks any one of which group will equally well servethe purpose oi the particular connection. It should be understood,however, that the invention is not limited to selectors of thischaracter, but may be used with equal advantage in connection withselectors in which connection is to be made with a particular lineterminating in the selector. Associated with the circuit 201, 202 by anysuitable means are the leads 213, 21a of the sender apparatus. Theconnection of these sender leads to the circuit 201, 202

may be either permanentor temporary as may be preferred, but since thisconnection forms no part of this invention it is only diagrammaticallyindicated as at 211, 212. Taking up now the description of the operationof the various parts shown in extending a connection through theselector shown in Fig. 2, the telephone circuit 201,202 will be assumedto have been connected through any suitable switching means to theconductors 301, 302 through the contacts 305, 306. At this time thesender leads 213, list are connected at the points 211, 212 to thetelephone circuit 201, 202. 'In order to accomplish a further selectionwhereby the telephone circuit may be extended to a suitable idle trunkline through the selector shown in Fig. 2, the controllers 221, 231 areset to indicate the respective main and secondary groups in which thedesired idle line is to be selected. For example, if the main group inwhich such line is to be selected is the fourth upon the selector thecontroller 221 will be moved in a clockwise direction until the pointerupon the handle 225 is adjacent the figure 3 upon the scale, the fourthmain group being characterized by the figure 3, the first main groupbeing characterized by the figure 0.. Similarly if the secondary groupin which the desired line is to be selected is the third in such fourthmain group the controller 221 having been properly set the controller231 will be moved until the pointer upon the handle 225 is adjacent tothe figure 2. Both controllers having been set it now only remains forthe operator to depress the starting button 271. It should be understoodthat this starting button, although heroin shown as an independentcontact device may equally well, in constructions in which thisinvention is involved, be represented when convenient in. a contactoperated by some art 01" the sending apparatus, moved after all of thecontrollers necessary for selection have been set,

The depression of the starting button. 271 closes the contacts 272,which establish a circuit from the ground 246,contacts 272, c0ndoctor,273, sequence switch contacts 292, conductor 219, cut-ofi relay 282, tothe free pole of the grounded battery 24:2. This energizes the cut-offrelay 282 causing it to 0p crate and by'its front contact 285 close acircuit from battery 212, conductor 277', se quence switchcontact 295,conductors 276 and 274:, sender sequence switch clutch inagnet 178 andstop magnet 193 to-ground and.

back to battery. This energizes the clutch and stop magnets, withdrawingthe stop pawl and causes the continuously rotating shaft with which theclutch is associated to drive the switch from rest into its first position. As has been heretofore noted the special sequence switch contact291 serves to insure the movement of the sequence switch fully to theposition desired even though the original energizing circuit for thesequence switch is broken as the sequence switch coin mences to move,and to accomplish this pur pose it closes a circuit from battery 2:13through resistance 217, sequence switch 221, conductor 27 1, sequenceswitch magnets 178, 193 and ground back to battery, at all times exceptwhen the sequence switch stands in. one of its designated positions. Thesends sequence switch having been moved to its first position, thesequence switch contacts 222 and 295 of the original energizing circuithave been opened and the sequence switch contacts and 296 closed. Asindicated by the figure adjacent to the quence switch contact 293, thiscontact is closed just before the opening of the contact 292 for thepurpose of continuing the energization of the cut oil relay 282 over thefollowing circuit, battery 242, relay 2S2, conductor 218, sequenceswitch contact 293,

conductor 280, contacts 220 of controller 221, conductor 281, contacts230 of controller 231 to ground and back to battery, The contacts 220and 230 of controllers 221 and 231 it will be noted have been closed bythe displacement of the controllers. The sender is now in readiness forthe first or main group selection.

Prior to the energization of the relay 282 a circuit existed from thebattery 241 through the relay 286, high resistance 21o, sender lead214:, contact 212, conductor 202, contact 306, conductor 302, individualse quence switch contacts 309, high resistance winding 310 of the linerelay 311, conductor 301, contact 305, conductor 201, contact 211,sender lead 21.8 and ground back to battery, The current in thiscircuit, however, due to the inclusion of the high'resistance 216 andthe fact that the winding 310 of the relay l of high resistanle, isinsufficient to either the relay 286 or the relay .1 However, upon thepulling u) of the armature 28E] of relay 282 a shunt is closed aroundthe high resistance 216and sufficient current thereupon passes throughthe circuit traced, to energize the relay 311, although not suilicientto energize the relay 286, due to the fact that the high resistance ofthe winding 310 is still included in the circuit, Upon the encrgizationof the relay 311 the armature 5512 is attracted and closes a cir cuitfrom the battery 313 through the armatur I, 312 nd its front contact,conductor 314, the closed contacts 315 of the off-normal switch 316,controlled by the pro'ection 317 upon the metallic tape 92, con uctor9-18, individual sequence switch contact 311?, clutch magnet 178, stopmagnet 193 of the individual, sequence switch 351 and ground back tobattery, The energization of the operating magnets 178 and 193 of theindividual sequence switch 351 causes it to move from rest or zeroposition to its first ositiou, the special individual scqu ence switc(amtacl; i'ltll'serving as did the sender sequence switch contact 291 toinsure the movement out the sequence switch 351 fully into its firstpositic-n. Upon this movement of the sequcsuce switch 551 the sequenceswitch contacts 319 and 390 are opened and the sequence switch contacts320, 321, 322, 323, 324, 325, 326 and 327 are closed all for purposeswhich will hereafter appear, The individual sequence switch contact 326closes a circuit from the bait ry 328 through conductor 329, releasemagnet 81, conductor 330, individual so Iii qucnce switch. contact 331and ground back j to battery to energize the release magnet 81., and thecontact 327 closes a circuit from but tery through conductor 333,individual clutch magnet 73 and ground back to bat tcry. .As long,therefore, as the individual sequence switch contacts 326 and 22? remainclosed the sheave 76 of the individual. driving); mechanism is coupledthroi the indivldual clutch to the master driving haft I57, and therelease magnet 81 encrg' ed to withdraw the projection 82 on thearmature 81 'from contact wit lhe teeth. '79,

The clo: e of the individual sr'uencc switch contacts 821, 322 and 323has closed a shunt circuit between the conductors 3G1 and 3502 aroundthe high resistance winding 310 of the line relay i-lll which includesthe winding 334; of the line relay 311 which ing i comparatively lowresistance. shunt circuit may be traced from the conductor 801, sequenceswitch contact- 321, winding; 33 1.- of the line relay 31]., individualsequence switch contact 322, coudi'ictor winding 4131 of the selectingrelay 4102, conductor 103, master sequence lilo ground back. to battery.

menses switch contact 404, commutator contacts 35 36, conductor 105,individual sequence switch contact to. the conductor The closure of thisshunt circuit through the winding 33a of the line relay 311 maintainsthe line relay 311 energized, energizes the selecting relay 402andrallews sufiicient current to pass to energize the stepping relay 286at the sender apparatus current for these various relays being sup--plied from the battery 24:1. The energization of the'relay 402 attractsthe armature -l-O6 and closes a circuit from the battery +107 throughthe armature 406 and its front contact, master sequence switch contact405. conductor 109, operating magnets 1T9 and 193 of the master sequenceswitch 451 and This circuit encrgizes the master sequence switch magnets17 8 and 193 and causes the sequence switch to move from rest or zeroposition a total of two steps into its second position, the specialmaster sequence switch contact 491 in this case being closed in thefirst position. so that the sequence switch when once moved from rest orZero position will continue to move until it reaches its secondposition. In passing; through its first position. howeverg'thc sequenceswitch contacts lOl hare momentarily opened and again closed the shuntcircuit above referred to. including winding 116 of relay 402 and groundbaelr to battery.

Upon the energization of the relay 286 by the closure ,of the shuntcircuit around the high resistance winding 310 of the line relay 311 acircuit wasclosed from the battery 244 through the magnet 228 of thecorn troller 221, sequence switch contact 297, armature, 287 of thestepping relay 226 and ground back to battery. T he closure or thiscircuit energized the magnet 228 which attracted its armature-and movedthe oscillating pawl 227 to release the segment half step. Thesubsequent deenergization of the stepping relay 286 due to the momentaryopening of the master sequence switch contact 40% caused thedeenereizati on of the magnet 228 due to the opening of the circuit tosuch magnet at the armature 28?. The deenergization o1": themaa'netallows its arn'iaturc to retract and the pawl 22? is again retractedunder the action of the half step. The master sequence switch 151 havingreached its second position the sequence switch contact iceis againclosed and the shunt-circuit around the h sistance winding 310 of tieline relay again established permitting; the reeneigization of thestepping relay 286, which again attracts armature and closes the cir uitto the magnet It should be noted that while the current in the circuit,while the shunt around the high resistance winding 310 of line relay Ellis open is insuiiicien' to energize the relay owing to the presence ofthe high resistance winding 310 there is still sutiicient currentthrough the high resistance winding 310 to maintain the line relay 311energized. Some time before the ma ter sequence switch 151 reached itssecond position. losed the sequence switch contact 110 as is indicatedby the characters 1-. 1. 2.3 adjacent thereto upon the drawing. Thisclosed a circuit from the battery 4-11 through the e c tromagnet of thechanging clutch 65, sequence switch contact stilt; and around hack tobattery. This circuit energ' the shaft 5? to be coupled directly to theshaft 29. so that when the shaft 29 mores the shatt 57 will more and atthe same rate of speed. Just before the sequence switch 451 reached itssecond position it closed, as is indicated, the sequence switch contact-land as it reached its second position it close; the sequence switchcontac u 413.

The closure of the sequence switch contact 112 at the time the sequenceswitch contact 408 was opened completed a circuit froin the battery 40?,armature 406 and its front contact, sequence switch contact 512,

ma gnet if and ground back to battery. The

stop in gnet- 43 having'been energized by the closure of this circuitattracts its urine-- ture 42 thereby closing a circuit through thecontact springs 17. 48 which may be traced from the battery 117, masterclutch magnet 25, contacts at, 4:8 and ground. back to battery. At thesame time the energization of the magnet has removed the stop formed byits armature from in front of the stop arm? 40. The closure of thecircuit through the master clutclrmagnet 25 couples the shaft 29 throughthe gearing shown with the constantly rotating shaft 15. The shafts 22and 57 will now more together and at the same-rate of speed beingdirectly coupled by the energization of the clutch 6S,

and the sheave 76 will revolve owing to the" the clutch magnet andcauses- The rotation of the shaft 29 has moved the dish 33 so that theshunt circuit around the high resistance winding 310 of the line relay311 is opened by the contacts 35, 36 resting upon the insulated portion418 of the disk. The rotation of the disk 3&1 with the shaft 29, has,however, closed a circuit to maintain the selecting relay 102 energizedwhile the shunt circuit .is 0 en, by the closure of a circuit from the vthrough the contacts 37, 3'8 and the metallic portion of the disk 34,conductor 420, winding 4:16 of the selecting relay 402 and ground backto battery. The opening of the shunt circuit around the high resistancewinding 810 of the line relay 311 at the contacts 35,

36 has again, as before, caused the decncrgization of the stepping relay286, which again causes the deenergization of the mag net 228 allowingthe segment 222 to complete a second step. As the shaft 29 continues torotate a circuit is again made through the metallic portion of the disk33 to close the shunt circuit around the highresistan-ce winding 310 ofthe line relay 311 and upon a slightly further rotation of the shaft 29the local energizing circuit of the selecting relay 102 through thewinding 116 thereof is opened by the contacts 37 38 coming upon theinsulating portion 421 of the disk 34. If

at this stage of the operation the high resistance 216 remains shuntedby the armature 283 of the cut-off relay 282, the rotation oi: the shaft29 and the consequent elevation of the brush carrier at the same relatirely high speed will be continued until the brushes have passed over asecond main group of contacts forming the terminals of the trunk lines,during which movement the segment 222 has been returned another steptoward normal due to the operation of the various relays as described inconnection with. the first movement of the contact carrier. When,however, the segment 222 of the controller 221 has reached its normalcondition due to the stepping operation controlled from the driving;mechanism, which will he, in the case assumed, after four make and breakimpulses have been sent back from the selector over the connectingcircuit, in the course of which the contact. carrier has l'l'iOVUClthree relatively long steps and passed over three main groups of contactterminals, the contact 220 will. be immediately opened and the cutoffrelay 282 thereby denergizcd. This will permit the retraction of thearmature 283 which will open the shunt around. the high resistance 216.WVhen now the rotation of the shaft has caused the opening of the localenergizing circuit through the winding 4.16 of the selecting relay 102and has again closed the shunt circuit around the high resistancewinding 310 of the line relay 311, insufiicient current Will passthrough. the winding 101 of the selectbattery 419" switch reached itsthird position.

ing relay 102, due to the presence in the circuit of the high resistance216, to maintain said selecting relay 402 energized and its armature 406will be retracted closing a circuit from the battery 407, sequenceswitch. contact/113, conductor 4109, operating magnets 178 and 193 ofthe master sequence switch 151 and ground back to battery which willcause the sequence switch to move from ts second positlon into its thirdposition. The movement of the sequence switch 451 into its thirdposition opens among others the sequence switch contacts 410 and-412.The 0 ening of the front contact of selecting re ay 402 has caused thedener ization of the stop magnet 43 which, when t e disk 39 is about toreach its nor mal position or" position of rest allows the armature 12to be retracted, opening the circuit to the master clutch magnet 25 atthe contact springs 17, 18 and stopping the rotation of the shaft 29 byobstructing the move ment' of the stop arm 40 as well as by releasingthe master clutch 13. The opening of the sequence switch contact 410has, just as the sequence switch reached its third position, opened thecircuit to the speed chang' ing clutch 68. It should be noted that, asindicated, the sequence switch contact 110 does not open until just asthe sequence These operations have brought the contact carriertemporarily to rest and the cooperative relations between the stoppindisk 39, the

stop arm 40 and the armature 4-2 oi. the stop conductor 274, operatingmagnets 178 and 193 of the sender sequence switch 251 and ground back tobattery. The energization of the magnets 178 and 193 of the sendersequence switch 251 thereupon cause the sequence switch to move from itsfirst position to its second position. As the sequence switch is movingfrom its first to its second position the sequence switch contact 294 isclosed and since the contacts 230 are closed, due to the fact that thecontroller 231 has been set, a circuit is established from hattcry 24:2,cut-ofli relay 282, conductor 218, sequence switch contacts 294,conductor 281, contacts 230 and ground back to battery. This circuitenergizes the cut-oil relay 282 which immediately attracts its armaturejust switch contact 294 between the first and second positions of thesender sequence switch is to prevent the establishment at this time ofan energizing circuit for the sender sequence switch 251, through thecontacts 284 and the sequence switch contact 200. The movement of thesender sequence switch 251 from first to second position has opened thesequence switch contacts 293 and 297 and has closed the sequence switchcontact 208, and the ma gnct 238-is now in condition to he(J01;tLIOllOCldJ} the stepping relay 280 over the circuitincliulingbattery 245, magnet 238, sequence switch contact 298, armature andcontact 287 and ground back to battery.

The energization of the cut-off relay 282 as the sequence switch 251reached its second position has again closed the shunt around the highresistance 210 at the armature 283. The closure of this shunt allowssutlicient current to pass to again energize the selecting relay 402over the circuit including the winding 401 of the selecting relay. Theselecting relay 402 thereupon attracts its armature 400 and closes thecircuit through its front contact and the sequence switch contact 408,which is closed at this time since the master sequence switch. is now inthird position, to energize the operating magnets 178 and 193 of themaster se quence switch 451. The master sequence switch 451 thereuponmoves from its third position into its fourth position, opening thesequence switch contact 408 and closing the sequence switch contacts412'and 413, the sequence switch contact 412 being closed just beforethe sequence switch reaches its fourth position as indicated upon thedrawing. The sequence switch contact 412 in closing has againestablished a circuit from battery 407, through the armature 400 and itsfront contact to the stop magnet 43, which as before, upon beingenergized, attracts its armature 42 to permit the disk 39 to revolve andto close the circuit for the master clutch magnet 25 at the contacts 47,48. The shaft 20 is thereupon again caused to revolve, driving with it,but at a. speed only one; tenth as fast as before (ft he shaft 57, thespeed reducing clutch 68,.being now unenergized and power is transmittedfrom the shaft 29 to the shaft 57 by means of the reducing gearing 51,54- and the pawl and ratchet mechanism 58; 5f). The brush carrier 88,mounted on the metallic tape 02, will therefore be moved, but-at arelatively low speed and for each rotation of the shaft 29 will passover but a single secondary group of trunk line terminals. r

In the rotation of the shaft the intermittent break and make of theshunt around the highs'esistance winding 310 of the line relay 311 isagain produced as in the former selecting operationthere being a singlebreak and make for each rotation of the shaft 29. Similarly the localenergizing circuit for the winding 416 of the selecting relay 402 ismade and broken each revolution Otthcshaft 20 to maintain the selectingrelay 402 energized until the shaft has rotated to the proper position.It will be noted, however, that in the second selecting operation nopreliminary break and make of the shunt circuit by the sequence switchcontact 40,1- occurred as was the case in the first selecting operation.This is'for the reason that while the selection of a. subsidiary groupin a main group is from the bottom to the top of such group theselection of a. particula r line iii a secondary group is from the topcontacts in this group downwardly until such line is found. That is tosay, if the line to be selected is, for example, in the third secondarygroup of the first main group, no long step of the brush carrier at therelatively high speed should be made, since three short steps at therelatively low speed will bring the bruslrcarrier to the top of thethird secondary group in such first main group, Similarly, in the *asefirst assumed in which the line desired is located in the fourth maingroup and the third secondary group in such main group, three long stepsat a relatively high speed were taken which caused the contact carrierto pass over three main groups and brought it to rest at the bottom ofthe fourth main group in which the line desired is located. Thereafter,three short steps at a relatively low speed will bring the contactcarrier to the top of the third secondary group, and selection will bemrde from that point downwardly, contact being made with each succeedingset of terminals until the desired line in such secon ary group isfound. This method of operation involving a preliminary break and makeof the circuit in shunt of the high resistance winding 310 of the linerelay 311 at the beginning of the high speed selection 0. a main groupof terminals is necessary in order that the controllers governing bothhigh speed and low speed selection may be uniform in structure andoperation, the preliminary break and make producing a full idle step fthe main group controller which n step compensates for the fact that thehigl'i speed selection is to the bottom of the desired main group ofterminals, \vliereas low speed selection is to the top of the desiredsecondarygroup of terminals \Yhile the contact carrier is passing overthe three secondary groups to reach the topof the secondary group inwhich the line tile sil'Od is to be found, the shaft 20 has been makingthree complete rotations and has caused the stepping relay to energizeand deiinergize the magnet 9.38 to allow the segment of the controller231 to again com to normal position. This has immedi atel'y'iopened thecontacts 230 and the cut fi relay 282 is thereupon again ocenergiaed andreleases its armatures This has opened the shunt around the highresistance 216 and when the local energizing circuit for the winding 416of the selecting relay 102 is again opened by the further movement ofthe commutator 34 insufiicient currcnt will. pass from battery 241 overthe selecting'cincult and the winding'etfll of the selecting relay 102to maintain such relay energized and it will thereupon allow itsEtlflIlEtlllllfJ 4:06 to retract. This opens the circuit to the stopmagnet d3 which thereupon stops the rotation of the shaft 29 by theretraction of its armature 42 into the path of the stop arm 10, at thesame time opening the circuit to the master clutch magnr-zt This bringsthe brush carrier to rest at the top oi" the secondary group in whichthe line desired is to be selected. The retraction oi. the arma-- tore406 has closed again an energizing circuit for the magnets 178 and 193of the inaster sequence switch 451, which thereupon moves to its normalor rest position. In so doing, however, the master sequence switch hasopened thecontacts 41.52 and 413 and has closed the contact 108. Theclosing and opening of these contacts, however, has no further efi'ectupon the operation of. the selector, but merely places this much of theapparatus again in normal position to serve some other selector, or thesame selector in connection with some subsequent call. passing, however,from the fourth position to normal position the master sequence switchmomentarily closes the master sequence switch contact 422. The closureof this con tact establishes a circuit from the battery 4153513,sequence switch contact a322, conductor 336, individual sequence switchcontact 894:, conductor 33-'?, operating magnets 1.78, 193 of theindividual sequence switch 351 and ground back to battery Theenergiaation of these magnets 178 and 193 causes the individual sequenceswitch to move from its first to its second position and in so doingit'opens the sequence switch contacts 8%, use, 326,627, 331 and clhses'the sequence switch contacts 338, 339 and 341, the sequence switchcontactBBS being closed just before the sequence switch reaches secondposition and being maintained closed in its second position, Theindividual mechanism has now released the master mechanism and is.

' ready to test for and select an idle line in the secondary group, thetop set of contacts of which the contact brushes are now in contactwith. Vl hcn the cut-ott relay Was dc energized, due to the opening ofthe contacts .230, and retracted its a matures, the circuit again closedfor the operating magnets and 193 of the sender sequence switch :lfromthe butt 2-. 2 through the za- ,1 and been contact and t This caused thesnitch contac;

In I

sender sequence switch to more from its second po' ion again into itsnormal position, and thereupon restored all oi: the seruler sequenceswitch contacts to their normal condi tlon.

lV hen the individual scrpionce switch 35]. in, moving into its secondposition closed the contact 338 it established a circuit for theumrginal test relay over the test conductor 343 connected. with the testcontact 8'iiot' the setof contact tcrn'iinals upon which the contactbrushes are now resting, At the distant end of the test conductor 343,and correspondingly with the test conductor of each. of the other trunklines, a battery I'll-t is connected through rc'" tunco The relation ofthe marginal t at relay to the current from the battery 344: is sozuljustcd.

. that it the line tested is idle, that is, if no other relay similar tothe t st relay Pill-i2 connected to the test conductor ii -l8, the ourrent from the battery 3M passing through the test relay 34-2 will hesullicicnt to attract the armature 346 and haying attractor l it to.rnainlaiu it attracted. even though another relay should be connectedto the test conductor Ii on the other hand, the trust: line tested isalready in use, a relay similar to the test relay 342 will be concd tothe test conductor 343, and insuf" at current will pass tlnrough thenutr- .1411 test relay 34:2 to energize it. A ssuinlug first that theline tested is idle, a circuit will he established from the distantbattery 34% through the resistance 8-15, test conductor 3A3, contactterminal. 87, testhrushes ill, conductor 34-7, sequence switch contactmarginal test relay 342 and ground hack to battery. The marginal testrelay will thereupon attract its armature 346 and upon the closure ofthe sequence switch contact when the individual sequence switch reachesits second position a circuit will he closed from the battery through.quencc switch contact 339, aianaturc 346 and its front contact,conductor 337, operating magnets 2.78 and 193 of the individual quenceswitch 83]. and grounrl hack: to batter-y. ouence switch to more fromits second. position into its third position, and in so doing open thesequence switch contac's $109, 352i, 339 and 341 and close the sequenceWitch. contacts 331, 349, 350, 3553 and The sequence switch contacts3-219 and 350 will, however, he closed just before the sequence switchreaches its third position and hel'ore the se quence switch contacts 309and 338 opened. A. circ "it will. thereupon he cstal'r lishod from thedistant battery ill-l; through the rt tance test conductor 343, testcontact terminal 87, test contact brushes 91, conductor 3-47, sequenceswitch contact 350, arr inc 3341. of the line relay fill, sequenceswitch contact h ld and groui'ul haul: to bat-- .lhis will cause theindividual tery. This circuit will energize the line to battery.

i cemsco relay and maintain it energized alter the se quence switchcontact-309 has opened the circuit oi the high resistance winding 310 ofthis relay, It should benoted that the relay 311 having been onceenergized will remain energized by current through the winding 310 fromthe battery 241 even though the shunt around the high resistance 216 beopened and it will only occur upon the opening of the sequence switchcontact 339 and the energizing circuit of the winding 334 at the sametime that the relay 311 will be denergized. The closure of the sequenceswitch contacts 352 and has coinpleteol the telephone transmissioncircuit 301, 302 to the contact brushes 39, 90 and thence through thecontacts 8-5, 86 to the trunk condoctors 303 and -l, selection andconnection having been completed.

The'return of the apparatus to normal is brought about by the opening ofthe circuit of the distant battery 34% connected with the test conductor3 23 of the trunk line which may be accomplished in any suitablemannerwhen connection hasceased This deenergines the relay 311 since theenergizing circuit of both windings are now open which permits theretraction of its armature 312 and closes a circuit from thcbattery 313through the aru'iuturc 312 at its back contact, conductor-35a, sequenceswitch contact 320, operating magnets 178, 193 of the individualsequence switch 351 and ground back The closure of this circuit causesthe sequence switch 351 to move from its third position into its normalposition, or position of rcst,'by which mmeincnt the sequence switchcontacts 319, 356, 352, and 320 are opened and the contacts 309, 319 and390 are closed. The closure of the sequence switch contact- 390 hasestablished a circuit from the battery 332, sequence switch contact 390,contact of the oil-normal switch 316, conductor 329, release magnet 81,conductor 330, sequence switch contact and ground backto battery' Thiscircuit will be maintained closed, due to the closure of the contacts335 of the (iii-normal switch, so long as the brush c: rrier is elevatedfrom its normal position, and energizes the release magnet 81 whichthereupon withdraws its armature from engagement with the teeth 79 uponthe sheave 76. The sheave 76 being now free to revolve, the individualclutch magnet having been heretofore dcenergized by the opening of thequence switch. contact 32?, allows the brush carrier 38 to descend ofits own wei 'h until it reaches its bottom or normal f; i-

, lion, in which position the projection 317 upon the metallic tape 92operates the ob?- iiorinal switch 316 breaking the circuit to therelease magnet Si and all the parts are again in their nonnalposition.

Assuming now that when the circuit to the marginal test relay 312 isclosed by the movementof the individual sequence switch from its firstto its second position that the trunk line connected to the top set. ofterminals o'tthe subsidia y group of terminals selected, with whidli setof contacts the contact brushes 85), 9-0 and 91 are now in contact, isbusy, In this case sullicicutcurrent from the battery Ill-l at thedistant point will not pass through the marginal test relay 3&2 toenergize it, this testrelay 3l2 beingshunted by similar relay orresistance at some other point upon the multiple of this particulartrunk line. The armature 346 of the test relay 342 will, therefore,remain retracted and the sequence switch reaches its second position acircuit will be established from the battery 3&8, through the sequenceswitch contact 339, armature 34:6 and its back contact, conductor 356,conductor 329, release magnet 81, conductor 330, sequence switch contact3-H, ulsator 357 and ground back to battery. The operation of thepulsator causes the release magnet 81 to be momcntarily energized andinuncdiately thereafter dci ncrp ized so that the armature S2 is attrusted and withdrawn from engagement with the teeth Tl) upon the sheave76, but is again immediately released before more than one of the teeth79 has passed thereunder. These teeth 79 are so adjusted that upon themovement of the sheave '76 the distance of one tooth the brush carrier83 will descend from a position to coiiperate with one set of contactterminals into position to cooperate and make contact with the nextsucceeding set of contact terminals therebclow. it now the trunk lineconnected to this set of contact terminals is also busy the marginaltest relay will remain decncrgizcd as before and the energizing circuitfor the release magnet 81 through the pulsator 357 will remainestablished. A further Vibration of the pulsator 357 will againmomentarily energize the release. magnet 81 and cause the contactbrushes to make contact with still another set of contact terminals.This step by step release and test of the setsot contact terminals willcontinue until a set of terminals is tested which is idle, whereuponsuflicicnt current will pass through the marginal test relay to cause itto attract its ari'naturc 3&8 and establish a circuit through its frontcontact from the battery 348 to cause the individual sequence switch 351to more into its third position has been heretofore described. From thispoint in the operation until the return of the apparatus to normal, theoperation is the same as has been already described in connection withthe operation of the apparatus when the first line tested was idle.

The operation of the master clutch mechanism and the speed reducingmechanism mechanism to normal. (i0

with any other of the individual apparatus associated therewith would beprecisel the same as with the individual apparatus s own in Fig. andhereinbefore described, the points 461, 462, 4.63 and lli-t indicatingthe converging points of the various circuits from the severalindividual mechanisms to the master mechanisms, and the dotted lineindicating the division between the master apparatus common to aplurality of selectors and the individual apparatus individual to asingle selector.

The sequence switch contact 425 closed at all times except whenthe-master sequence switch is in. its rest or normal positionestablishes a circuit, when the relay 427 is deeuergizcd, which passesfrom the battery 41:26, sequence switch contact 425, armature 428 andits back contact, conductor 409, operating magnets 178 and 193 of themaster sequence switch 451 and ground back to battery. Upon the closureof this circuit the master sequence switch 4:51 will be moved into itsnormal or rest position no matter at what point in its operation thecircuit was closed and in so moving will restore all ot the apparatusassociated with it to normal condition. However, to prevent thisrestoration under proper workingconditions a circuit provided for therelay 427 from. the battery 313, armature 31.2 and its front contact,conductor 358, sequence switch contuctrelay 4?? and ground back tolnittery. The relay 427 will. therefore be maintained energized undernormal conditions dulring the entire operation of tlie master sequenceswitch 151, but immediately that the master sequence switch complctcsits cycle oi? operations, that is as it is returning to 'nial themomentary closure of the contact i: 9 causes the individual se quenceswitch to move out of its first position. and thereby opens the contact325 in the circuit of the relay 12T.

The utility of the relay: 427 and its associated circuits to insure thereturn of the a l l)aratus hoth master and individual to normalcondition through any al'morn'ial failure oi current over the circuit301. 302 while selection is in progress. This is ac complished by havingthe circuit to the relay 427 controlled by the armature 3 2 of the relay311. Should this relay till he deiincrnixed at any time during selectionwhich, deencrcizzation could only he the result of some almorlinilcondition the rctractim of the armature 312 would open the. circuit tothe relay 12? causing it to restore the master At the same time thearmature 3 would close at its rear contact a circuit from the battery31th armature 3152 and its rear contact, coiuluctor 354-, sequenceswitch contact 32th operating magnets 178 and 193 ot the iiulividualsequence switch Sailio ground back to battery. This circuit group ofselectors associated. therew combination with selector switches each irier in such selecting position, and niieai since the contact 320 isonly open Wl'lfi'il ll individual sequence switch is in norm" I restposition will insure the return individual apparatus to normal couduF Bythese means the failure of current ucircuit 301, 302 cannot possibly tieup the master mechanism and thereby the l l I i, the particularindividual mechanism cl" selector associated with such circui t Itshould be understood that while various sources of current hereinSililWl: a. it indicated as separate and indepcnrflcur: those which areof like polarity and and which are located 111 the same may be, andpreferably are, one and to source of current.

1. In a tclephrnie exchange 2; combination wlth a selector a jq iarul'uing a movable contact member id gut contact terminals arranged.vertically extending row "wi u member cooperates, means for cle contactmen'ibcr past said. contact to select a group thereof, and me trollingthe descent of said under the influence of gra'v selection of a contactti'arminiil group. i

2. In a telephone exchange syst l combination with a s lector apparing amovable conliac'; member aiul terminals with which said memluu: ates,means for im iiarting to said member selective movements at speeds pastsaid contact tcrmiuul. direction and means for caau in selectivemovement by said co in the opposite direction.

3. in a tclcqihonc exchange sv ing a movable contact meander.IllGCllzllllSlll common to the cor of a. plurality ot said switches,sehrtion Cilll trollingv means, means for individually r nectiug saidcontact members to'said in mechanism under the influence oi tioncontrolling means, and means 'loi' parting to said contact members a furmovement indc'peiulcntlj of said. cor motor mechanism.

4. In atelephone exchange sjstuni combination with a connecting cirinut,selector comprising a mowihle brush cal and groups of line terminalsarranged rows in a panel bank, driving means lo mo ring; said brushcarrier in one diucctiijru, a sender device associated with said conncingr circuit for controlling said driving meaiti to move said brushcarrier to'select a group of line terminals, electromagneticully con--trolled means for retaining said lirush ur operating said retainingmeans to intenii tently release said brush carrier and allow it to bemoved step by step until an idle line has been found.

In a telephone 'exchange system, the combination with a connectingcircuit, of a selector yswitch comprising a movable brush carrier andgroups'o'f' line terminals arranged in substantially verticallyextending rows in a panel bank, electromagnetically controlled drivingmeans for, moving said carrier, a sender associated with said connectingcircuit for controlling said driving means to move said brush carrier.ertically to select a group of terminals and electro- Inagneticallycontrolled retaining means intermittently operated to allow said carrierto select a desired line in said group.

6. In a telephone exchange system, the

combination with a connecting circuit, of a selector switch comprising amovable brush arrier and groups of line terminals arranged in rows in apanel bank, electromagnetically controlled. power-driving means formoving said carrier, a sender associated with said connecting circuitfor controlling said driving means to move said brush carrier in onedirection to select a group of terminals,

and electromagnetically controlled retaining meansintermittentlyoperated to allow said .xcarrierto select an idle line insaid group.

7, In a telephone exchange system, the combination w1tl1 a connectingcircuit, of a Selector switch comprising a movable brush means to causesaid brushcai'rier to select agroup of line terminals, retaining meansfor said brush carrier, a release magnet controlling said retainingmeans, and means intermittently energizing said release magnet torelease said brush carrier step by step until an idle line has beenround.

8. In a telephone exchange system, the

combination with a connecting circuit, of a selector switch comprising amovable brush carrier and groups of line terminals arranged invertically extending rows in a panel bank, driving means for saidcarrier, a sending device associated with said connecting circuitarranged to control said driving means to elevate said carrier to selecta group of line terminals, eleclromagnetically controlled means forretaining said carrier in elevated position, and means for operatingsaid retaining means to release said carrier step by step until an idleline has been found. In witness whereof, I hereunto subscribe my namethis 8th day of August A, 1)., 1912.

AMOS F, DIXON.

Witnesses: y

W ALTER FREDERICK HOFFMAN, ELLA EDLER.

